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根据管线钢的使用要求,采用热模拟技术、显微分析方案和力学性能测量手段,对热处理过程中化工管道用L830管线钢焊接接头的组织及力学性能的变化进行了研究。结果表明:焊接后L830管线钢母材的微观结构主要为铁素体和粒状贝氏体,在铁素体的晶界上分散的是粒状的贝氏体;焊接接头主要由针状铁素体和粒状贝氏体组成,热影响区为铁素体,但是形态不同,在粗晶区有准多边形和多边形之分,细晶区大部分由铁素体组成;焊缝区的硬度能够达到382 HV,焊接接头不仅具有较高的强度,还具有很好的韧性,能够满足化工管道用L830管线钢焊缝的力学性能要求。
According to the requirements of pipeline steel, the changes of microstructure and mechanical properties of L830 pipeline steel welded joints during heat treatment were studied by means of thermal simulation, microscopic analysis and mechanical properties measurement. The results show that the microstructure of the base metal of L830 pipeline steel after welding is mainly ferrite and granular bainite, granular granular bainite is dispersed on the grain boundaries of ferrite. The welded joints are mainly composed of acicular ferrite And granular bainite, the heat affected zone is ferrite, but the morphology is different from that of the quasi-polygons and polygons in the coarse-grained zone. Most of the fine-grained zone is composed of ferrite. The weld zone hardness can reach 382 HV, welded joints not only have high strength, but also have good toughness, to meet the chemical pipeline L830 pipeline weld mechanical properties.